The invention pertains to a metal dowel to be anchored in thin wall boards made of plasterboard, pressed wood or similar building material, wherein the dowel shaft is formed from a sheet metal plate and provided with semi circular retention ridges punched out of the shaft and projecting alternately to each side, which are matched in width and pitch to the thread shape of the screw to be tightened such that the retention ridges engage into the thread grooves of the latter.